Include undercloud private IP as a stack output

This will allow quickstart to bind the UI apache to the correct
interface.

templates/quintupleo.yaml

@@ -253,3 +253,7 @@ outputs:
     description: "floating ip of the undercloud instance"
     value:
       get_attr: [undercloud_env, undercloud_host_floating_ip]
+  undercloud_host_private_ip:
+    description: "ip of the undercloud instance on the private network"
+    value:
+      get_attr: [undercloud_env, undercloud_host_private_ip]

templates/undercloud-volume.yaml

@@ -73,3 +73,12 @@ outputs:
     description: "floating ip of the undercloud instance"
     value:
       get_attr: [undercloud_floating_ip, undercloud_host]
+  undercloud_host_private_ip:
+    description: "ip of the undercloud instance on the private network"
+    value:
+      get_attr:
+      - undercloud_server
+      - addresses
+      - {get_param: private_net}
+      - 0
+      - addr

templates/undercloud.yaml

@@ -59,3 +59,12 @@ outputs:
     description: "floating ip of the undercloud instance"
     value:
       get_attr: [undercloud_floating_ip, undercloud_host]
+  undercloud_host_private_ip:
+    description: "ip of the undercloud instance on the private network"
+    value:
+      get_attr:
+      - undercloud_server
+      - addresses
+      - {get_param: private_net}
+      - 0
+      - addr